In semiconductor technology, rotary or spin-coaters, which are also called coaters, are already known in many embodiments, in particular for the application of photoresist to substrates such as wafers or glass plates, but are also used for applying other liquid media.
For reproducible production processes having a high yield, it is a decisive criterion to also be able to apply the liquid medium, such as a photoresist, in the most homogeneous layer possible, even for applications involving comparatively large substrates.
In one embodiment, a covering unit used for the “spinning process” is lowered over the substrate to be coated. By using this, the intention is to produce a solvent cushion on the substrate or the liquid medium applied, which leads to the formation of a more uniform layer during the spinning operation. Without any covering, a normally laminar flow in clean rooms would result in undesired “drying out” of the liquid medium to be applied.